1. Field of Invention
This invention relates to flexible tubing with annular corrugations and especially to a coupling device for connecting an end of such tubing to a fitting. The device includes a latch attached to an end of the tubing and a catch associated with the fitting. More particularly, the invention relates to a unique means for attaching the latch to the end of the tubing.
2. Description of Related Art
Examples of flexible resilient tubing with annular corrugations are shown and described in U.S. Pat. Nos. and 3,669,586, 3,705,780 and 3,809,522, and also in co-pending U.S. patent application Ser. No. 13/489,147, filed Jun. 5, 2012. These references are referred to below and are incorporated by reference herein.
Such tubing is both flexible and resilient and also crush resistant. In addition, the tubing has a wall that defines both internal and external ridges and grooves along at least a portion of its length. In other words, the wall portions that define the annular external ridges, also define on their opposite side, the annular internal grooves. Typical applications for this type of tubing include farm machinery, particularly seeding equipment.
This type of flexible tubing may be made for example, using the methods and apparatus shown and described in the above patents and pending patent application. In general, the process begins with a sleeve of uncured rubber of the desired length, width and wall thickness. The sleeve is placed on a mandrel and an external forming member is placed around the mandrel and sleeve. The forming member has a plurality of annular discs which are connected in various ways to keep them in uniformly spaced relation and to permit the forming member to be axially extended and collapsed to vary the spacing between the discs.
Then fluid pressure is applied between the outer surface of the mandrel and the inner surface of the sleeve to expand portions of the sleeve into the annular spaces between the discs. With the sleeve in this expanded condition, the external form may be axially collapsed or foreshortened with annular wall portions of the sleeve still within the constricted annular spaces between the discs. This causes the radially expanded wall portions of the sleeve to be squeezed in accordion fashion between the discs to form preliminary annular impressions in the uncured rubber.
Next, the fluid pressure is released and the external forming member is axially extended together with the sleeve to permit the sleeve to be removed from the mandrel and external forming member. The resulting sleeve with the preliminary annular impressions formed thereon is placed on a curing mandrel where it is axially foreshortened into an annularly corrugated form with the desired spacing between adjacent corrugations. Finally, the sleeve and the curing mandrel are placed in an oven and heated to cure the sleeve and set the corrugations.
When an annularly corrugated tube of the type described is assembled with associated equipment, it is usually necessary to connect one or both ends of the tube to a fitting with a passage to be aligned with the passage through the tube. To accomplish this, the fitting is typically provided with a flat annular end face and the annular side wall of the forward most ridge on the tube is placed tightly against this face. In order to keep the side wall of the forward most ridge pressed against the end face of the fitting, it is necessary that the end of the tube and the fitting be connected in a tightly latched condition.
Also, in order to assure a tight fit, it is desirable that the respective side wall of the forward most ridge be flat. The normal shape of the ridges and grooves of the corrugations is somewhat sinusoidal in cross section so that the side wall portion is normally curved. The result is that the side wall portion does not make good surface-to surface contact with the end face of the fitting.
The present invention resolves this problem and affords other features and advantages heretofore not obtainable.